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Behind the Scenes of the IPCC

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"Behind the Scenes of the IPCC"


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The IPCC Fourth Assessment is out, as is news of the political process and “last-minute wrangling” that gave us the final product.

Two topics were especially controversial. The first is the relationship between hurricane intensity and climate change. Predictably, the U.S. lobbied for weak language on the topic. One blogger on RealClimate notes that Europe’s news coverage hardly emphasizes the point. Or is that because Europe isn’t hit by hurricanes?

Second, the IPCC models leave out significant melting of the Greenland and Antarctic ice sheets, as ClimateProgress has noted and RealClimate also observed. As Drew Shindell, from NASA’s Goddard Institute for Space Studies, put it:

The melting of Greenland has been accelerating so incredibly rapidly that the I.P.C.C. report will already be out of date in predicting sea level rise, which will probably be much worse than is predicted in the I.P.C.C. report.

While the Fourth Assessment is a valuable contribution, it is still a conservative, already-out-of-date summary targeted at policymakers, who aren’t as easily pushed into action as, say, the melting glaciers.


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One Response to Behind the Scenes of the IPCC

  1. hippie with a pistol says:

    “Predictably, the U.S. lobbied for weak language on the topic.”

    I believe you are mischaracterizing the negotiations within Working Group I. I would say that including the the recent consensus statement from the WMO is not lobbying for weak language.

    See the International Institute for Sustainable Development (IISD)
    Earth Negotiations Bulletin:


    “Regarding tropical cyclones, the US drew attention to
    a consensus statement produced at a recent WMO cyclone
    workshop about the difficulties of detecting cyclone trends, and
    cautioned that using the terms “global” and “trend” to describe
    an increase in the intensity of tropical cyclones could open the
    IPCC to criticism.”

    As for a little insight on the negotiations on why the IPCC left out some aspects of recent observations on melting ice sheets:

    “Regarding projections for sea level rise and changes in ice flow, the Coordinating Lead Authors expressed frustration that it was not yet possible to include the full effects of ice sheet flow in the models. Germany stressed the potentially important contributions from melting of the Greenland and Antarctic ice sheets. Austria underscored the importance of reflecting in the text that the rates are current best estimates, but that they could increase or decrease in the future. Germany emphasized the need for clarity on what is and what is not included in the sea level rise projections, and Kenya, Sudan, the US, Canada, and others asked that the language remain understandable.

    “Participants decided to add a sentence proposed by the UK stating that models used to date do not include the full effects of dynamical changes in ice flow, and to include this understanding within the projections table (Table SPM-2). Belgium suggested, and participants agreed, to make it clear that uncertainties in climate-carbon cycle feedbacks are also not included in sea level rise projections due to lack of published literature. Noting recent observations on accelerated ice flow, Germany requested additional language indicating a discrepancy between positive recent observations of ice sheet flow and negative projections from models. Participants decided to note that dynamical ice flow processes are not included in the models, but suggested by recent observations, could increase future sea level rise.”